Variable change speed hoist



T. o. DAVIDSON v2,333,092

VARIABLE CHANGE SPEED HOIST Filed March l2, 1 941 Nov. 2, 1943.

IVENTOR.

ATTORNEY Patented Nov. 2, 1943 VVARIABLE CHANGE SPEED HOIST Trevor O.Davidson, Milwaukee, Wis., assigner to Bucyrus-Erie Company, SouthMilwaukee, Wis., a corporation of Delaware Application March. 12, 1941,Serial No. 382,923

Y Y 6 Claims.

My invention relates to new and useful improvements in hoists, moreparticularlyto the hoisting mechanism of lexcavators of the type havinga boom and an outward digging clipper mounted on the end of a handle,which handle is reciprocable with respect to a point on the boom knownas the shipper shaft, the dipper being movable in a circle about thispoint as a center.

The hoisting line usually extends from a winding drum on the main frameof the excavator, over a sheave on the outer end of the boom, to theclipper and handle, and thence over another sheave on the boom to ananchorage on the boom.

Frequently it is desirable that the operator of such an excavator beable to change the speed of hoisting the dipper, and be able to makethis change of speed at selected points of the hoisting cycle. Thus whenthe dipper is digging, it is desirable to move it at low speed with highapplied force; and when the dipper is hoisting, or is doing lightdigging, it is advantageous to move the dipper at high speed with lowerapplied force. Furf thermore, since digging conditions differ on eachjob, the point in the hoisting cycle at which the speed is changedshould be variable, but once the point has been determined for any givenjob, the change of speed should thereafter be automatic throughout thatjob. Lastly, the means for accomplishing the change of speed and forvarying the point of change speed should be simple and l inexpensive.

Accordingly it is the principal object of my invention to provide, forcontrol of the hoisting line,

the novel combination of a multiple-diameter winding drum and a variableanchorage, whereby the hoisting speed may be changed automatically,

and the point of change speed may be varied.

Another object resides in the provision of v means for Varying thepoint-oi` change speed, which means is independent of the means forchanging hoisting speed, and is simple to construct and to operate.

In addition to my principal objects, I have worked out a number'of noveland useful details, which will be readily evident as the descriptionprogresses.

My invention consists in the novel parts, and in the combinations andarrangements thereof, which are dened in the appended claims; and ofwhich two embodiments are exemplied in the accompanying drawing, whichis hereinafter particularly described and explained.

Throughout the description, the same reference number is applied to thesame member or to similar members.

Referring to the accompanying drawing, it will be seen that:

Figure 1 is a conventionalized side elevation of an excavator equippedwith my invention, showing the dipper in two positions. In the diggingposition, the clipper and the hoisting-line are shown by full lines; inthe hoisting position, they are'shown by dotted lines.

Figure 2 is a rear elevation of a two-diameter drum, taken along thevlines 2 2 in Figure 1. This is one embodiment of a part of myinvention.

Figure 3 is a similar rear elevation o-f a tapered drum,'which isanother embodiment of the same part of my invention.

Referring now more particularly to Figure 1, we see that I haveillustrated an excavator or power shovel of a conventional type,omitting, however, certain details as not essential to an understandingof the invention. Well known details of this type of excavator are: themain base II which is ordinarily revolvable o-n a propelling tractionmounted base (not shown) ;V an upwardly inclined boom IZ pivoted at itsfoot to the base II; a suspension (not shown) for the boom; a clipperhandle I3, carrying at its outer end a dip per I4; and a power drivenshipper shaft I5 journalled on the boom for eiiecting reciprocation ofthe dipper handle. The method of driving this shipper shaft isimmaterial to the present invention. Thus it may be driven by an engineI8 located .adjacent toit (as shown in Figure l), or by any otherconventional expedient. A hoisting Winch or drum I'I, driven by anvadjacent engine I8, is 'shown mounted on the base, although it may bemounted on any other part of the machine which in turn is supported bythe base. A hoisting line I 9, anchored andwrapped upon thishoisting-drum, is trained over one of the sheaves 20 at the outer end ofthe boom, to a sheave 2| on the clipper, and thence over another sheave20 to an anchor 22 on the boom. The hoisting line may consist cf a rope,chain, or other flexible tension member.

A principal element of my novel hoisting mechanism is themultiple-diameter hoisting drum I'I, two embodiments of which are shownin Figures 2 and 3. In Figure 3 the barrel of the drum is tapered andprovided with a continuous groove 23 for guiding the hoisting-line fromthe'small to the large end of the drum and vice versa. In Figure 2 thedrum is formed with two portions 24 and 25 of different diameters. Thegroove 26 at the large end 24 of the drum is connected with `the groove21 at the small end 25 thereof by a transitional groove 28. In bothtypes of drum the hoisting-line I9 is anchored at 33 on the small lowspeed end 25 of the drum and is wound on the drum up over the large end24. The direction of winding depends on the direction in which thegroove is cut. For example, in Figures 2 and 3 the grooves are yshownrunning clockwise from the small to the large end (considering the 'drumas viewed from the right as in Figure 1). Winding the hoisting-line upon the drum eiectsav change from low-speed high applied` force `tohigh-speed low applied force. Ifthedriunillustrated in Figure 2 isemployed, this change occurs suddenly at a point in the-hoistingcyclewhich.

is determined by the adjustment ofthe variable anchorage which is thesecond important element of my invention.

In Figure 1 one form of variable anchorage is shown on the upper part ofthe boom. The illus- :itrated form- 'of .anchorage 'consists 1 of 1a.plate 1,2 9

mounted lengthwise on the boomlandperforated 'with longitudinallyspaced: holes v3!) iorr'eceiving a removable pin or bolt 3| to whichthefhoistingfline" l 9: is "dead ende'd. Itiis funderstood, however, @thatmy" invention i is fnot limited to 'this :particular 'fform y'ofvariable f-anchorage,v fbut coverspany :adjustable I.or operable device,preferably rindezpendent Aoffthe Ahoistingrneans,A` whereby the workingportion of the hoisting-linefmay' be' shortened or 'lengthened Changing'the point of anchorage,

.'byinserting theanchorage pin or bolt in another "hola-'or byadjustingor operating any other 'form eofrvariable .anchorage idevic'e, 'effectsa Vchange in @the pointof Xchange speedin the hoisting'cycle, 1

and also shifts the point airone-wear.

'znwFigure '-1`full lines showt'hedipper in'v digging posit-ion, with'the hoisting line 1on the'low speed small diameter portion ofthe drum'and dotted t lines 'show 'the clipper in'hoistingposition, 'withythehoisting'line.onthe highspeed large 'diameter ,iportion of the drum.If digging is light, the dip- )per -may beioperated at high-speed inboth fthe `digging andhoistin'g positions by `vdead-ending the:hoisting-line at the outer v'anchorage f32, since the point :of changespeed will then bevat the Ilowest fextremelof Vthe hoisting cycle,andonlyline'wound 7onthe large diameter portion 24ofthe'drurn` willfbefactive. Conversely, if vthe ldigging is heavy, @the-dipper maybevoperated at low `speed in both ldiggin'gandhoistingpositions bydead-ending the :hoisting-line at the inner'anchoraga 'so that'onlyVline wound on the small `diameter portion `25 of the .drum will 'beactive.

Havingnow described-'and illustrated one yform Vof'my inventio-n,'I'wishit tobe understood that :my invention is` not :to be limited to theYspecific .lfcrm lor arrangement of parts .herein-described and shown,except as lsp'ecilically coveredby my claims.

AI claim:

1. In a power shovel, Ithe Vcombination tof: Va boom; 4guide sheaves onthe boom; a ydipper fhandle; a dipper carried by thehandle; means forreciprocating the clipper handle; a ymultiple 'diamet'erhoisting drumformed with'aoontinuous'cable-guiding-groove; anda hoist rope having ailive `end and a dead end, its live bend being iattached to and wrappedupon the hoisting drum,

trained over lthe guide sheaves, and connected with the dipper, and itsdead end being attached to an anchor selectively positionable in anumber of positions, to vary what diameter of the drum is eiective indifferent portions of the hoisting cycle, by means including adjustablepin connection means mounted along the length of said boom for anchoringthe hoist rope at any one of a plurality of longitudinally spaced pointsalong vsaid boom.

2. In a power shovel, having: a boom, a dipper handle, and a dppercarried by the handle, the

vcombination therewith of: a flexible hoist member having a live end anda dead end; a winch wcapable, lata constant speed, of imparting variablespeed yto the live end of said hoist member, de- `.pendent on the degreeof travel thereof; and, in-

dependent of such winch, an anchor for the dead end of said hoistmember, said anchor being selectively positionable in a number ofpositions to vary what degree of travel occurs in different portions ofthe hoisting cycle.

3. In ua hoist, 'the combination of: a load fhandlin'gimeans; aflexible. hoist member having a live end and a dead end; a multiplediameter "hoisting ldrum for imparting variable speed to the live end'ofsaid hoist member; and an anchor for the dead `end of said hoist member,said anchor fleeing selectively positionable in a number of positions to`vary what diameter of the drum is effective in different portions ofthe hoisting cycle.

4. In `a power shovel, v'the combination of a boom; guide sheaves on theboom; a dipper handle; 'a clipper carried by the handle; means forreciprocating the Clipper handle; a multiple .diameter hoisting drumformedv with a continuous cable-'guiding groove; and ahoist rope having'a live end'and 'a dead end, its live endbeing a'ttached to thesmall'diameter end of said Ydrum and wrapped upon the small 'and largeVdiameter portions of `said hoisting drum, trained over the,guidesheaves, and connected with thedipper, and 'its dead endYbeing'atta'ched toadjustable pin'conr`ne'ctio-n means mounted along'thelength of said boom for anchoring the hoist rope at anyone of laplurality of longitudinallyspa'ced points along choring the iiexiblehoist member at any one of a plurality of longitudinally spaced pointsalong said bo-om.

6. In a hoist, the combination oi t' load handling means; a exible hoistmember having a live end and a dead end; a multiple diameter hoistingdrum for imparting variable speed to the live end of said hoist member;and an anchor yfor one end Vof said hoist member, said anchor includingadjustable pin connection means for anchoring said hoist member at anyone of a plurality of spaced points.

rTRES/ORv O. DAVIDSON.

